#include<stdio.h>
int main()
{
    char A='a';
    switch (A)
    {
        case 'a':
            printf("ouput A!\n");break;
        case 'b':
            printf("ouput B!\n");break;
        default:   //yi shang qing kuang dou bu xing
            printf("ouput Node!\n");    
    }
    return 0;
}